Roberto Martinez and Everton have been dealt a blow despite beating Queens Park Rangers 3-1 at Goodison Park on Monday night.
Star man Kevin Mirallas was brought down by Jordon Mutch in stoppage time, and appeared to be in some pain with his ankle.
The attacker left Everton on crutches and with his foot in a boot at the end of the night, according to ITV, which will leave both staff and fans with fingers crossed as to hope he is back in action sooner rather than later.
Mirallas was one of the most underrated players in the league last season, scoring nine goals in all competitions and providing a different attacking option for Everton.
He has already bagged six goals in all competitions so far this campaign, including the free-kick which put the Toffees 2-0 up in the first half against Harry Redknapp's side.
The injury took a big part of the joy out of what was a good win for Martinez' side, who got back to winning ways after three matches without a win.
EXTENT OF INJURY
The extent of the injury to the attacker is unknown, with scan results likely to be released later today with details of a time period for his absence.
Martinez did give fans some hope, after explaining that the swelling to Mirallas' ankle happened immediately.
"I don't know if it's going to be ligament damage or something else. We're going to scan him in the morning. It doesn't look too bad. It's swollen straight away, which is a good sign," the 41-year-old said.
Ross Barkley opened the scoring with a fine strike just after the half an hour mark, before Mirallas' deflected free-kick put the hosts 2-0 up.
In-form Steven Naismith all but wrapped the game up, when he scored Everton's third in the 53rd minute. A Bobby Zamora consolation goal made it 3-1, however QPR's terrible away form continued.
Up until conceding the first goal, the Hoops seemed relatively comfortable and even created some chances of their own.
"Until they scored their first goal, I've never felt so comfortable. I thought, 'We've got a big chance here tonight'," Harry Redknapp said.
"The crowd was edgy, I thought they played edgy. Even at 3-1 with 10 minutes to go, they weren't exactly full of confidence."